A quick note on gethead of WCSTools – as I have needed many times (but obviously not that many to remember it!). Rather straightforward use: gethead HEADER_KEY image.fits (as simple as possibly!) If HEADER_KEY contains empty spaces then use double quotes, e.g. “HIERARCH TEL AIRM END”. Reminder: you have to …
Although hedit of IRAF is supposed to handle the keywords of a fits file (add, remove) its behaviour can be misleading sometimes. An error like this: ERROR (1121, “FXF: EOF encountered while reading FITS file (something.fits)”) means that after altering the keywords in the header the EOF of the header …
In order to get a specific field from the header of a file you can use the command: cl> imhead inage.fit l+ | grep name_of_field In case you want to do it for many files you just use the wildcard: cl> imhead inage*.fit l+ | grep name_of_field Not very sophisticated …